Process of utilizing liquefied gas for railway-traffic-controlling apparatus.



No. 810,263. PATENTED JAN. 16, 1906.

0. W. COLEMAN. PROCESS OF UTILIZING LIQUEPIED GAS FOR RAILWAY TRAFFIC CONTROLLING APPARATUS.

APPLICATION FILED DEC. 12, 1904 UNITED STATES PATENT orrron.

CLARENCE W. COLEMAN, OF WESTFIELD. NEW JERSEY, ASSIGNOR TO HALL SIGNAL COMPANY, A CORPORATION OF MAINE.

PROCESS OF UTILIZING LIQUEFIED GAS FOR RAILWAY-TRAFFlC-CONTROLLING APPARATUS.

Specification of Letters Patent.

Patented Jan. 16, 1906.

Application filed December 12, 1904: Serial No. 236,458.

To all w/tmn, it may concern:

Be it known that I, CLARENCE W. COLE- MAN, a citizen of the United States, and a resident of Westfield, county of Union, and State of New Jersey, have invented a new and useful Improvement in the Process of Utilizing Liquefied Gas for Railway-Traffic- Controlling Apparatus, ofwhich the following is a specification.

The object of my invention is to utilize the expansive force of a gas initially under high pressure to operate a railway-tra'ffic-controlling apparatus.

One object of the invention is to prevent a rise in pressure of the gas above a predetermined amount as it passes through or while in the pipes of the apparatus. The gas that I prefer to utilize is one that is liquefiable at ordinary temperatures, and in the best embodiment of my invention I use the gas derived from liquefied carbonic acid.

In the operation of railway-traffic-controL ling apparatus, whether signals or switches, by means of the expanding force of a gas initially under high pressureas, for example, carbonic-acid gas, preferably at or near the pressure of liquefactionit is necessary to provide some means for reducing the pressure of the gas before it is admitted to the motor which actuates or controls the signal or switch. One means for accomplishing this reduction of pressure is a reducing-valve. It is also customary to provide an admissionvalve for admitting the gas at the reduced pressure to the motor. This admissionvalve is usually controlled by electrical.

means, which is in turn controlled by a train. I have found that the pressure of the gas will sometimes rise above the pressure to which it has been reduced by the reducing means and that this rise may be sufficient to exert an objectionable pressure .upon the admission-valve. The means used to actuate the admission-valve which is able to actuate this valve under normal conditions may be insufiicient to move the valve when the latter is subjected to the increased pressure of the gas. I have discovered that this objectionable increase in pressure of the gas when carbonic-acid gas is used is due to the formation of carbonic-acid snow produced by the chilling of the gas. This snow becomin trapped between the admission-valve and t e reducing-valve will be converted into high-pres sure gas by the heat received from external sources, such as the atmosphere, and this pressure will give rise to the di'fliculties above mentioned. An object of my invention is to prevent the rise in pressure of the gas and the injurious effects that may result from the formation of snow out of the gas that is used. I have found that this objectionable rise in pressure occurs particularly in winter when the parts of the apparatus are cold and that in summer some of the difficulties that arise in connection with the use of the apparatus in winter are not experienced.

My method for preventing rise in pressure of the gas above a predetermined point may be widely varied. This may be done either by preventing the formation of snow or by preventing too great a rise in pressure resulting from the gas ification of any snow that may have been formed. In accordance with my method brief, intermittent, and small demands are made on liquefied gas and on the gas utilized in the system, so as to avoid deleterious temperature changes, especially such as would produce freezing of the parts or solidification of the gas. Furthermore, in the best embodiment of my invention the demands on the gas-supply last during short periods of time and are succeeded by longer intervals of rest, during which the gas in the reservoir becomes heated to the temperature of the surrounding atmosphere. Furthermore, in the best embodiment of my invention the liquid is converted into gas slowly,

and the pressure is reduced slowly from the pressure of liquefaction to the pressure of utilization, and heat is supplied to the gas rapidly and in large amounts as compared with the amount and rate at which work is done by the gas. a

In the best embodiment of my invention I permit the gas to flow into, expand into, and be stored in a reservoir of a suitable capacity, and thereby achieve a number of important results. If any snow is formed by the evaporation of the liquid or by the rapid expansion of the gas, the reservoir is of sufficient capacity to prevent the rise in pressure of the gas from exceeding a predetermined amount. Moreover, the formation of snow is hindered or prevented, and the formation of large quantities of snow is revented, since the additional capacity of t e reservoir diminishes the rate of evaporation and of the expansion and conse uent cooling of the gas as it passes throught e pressure-reducing means. Again, the stored gas absorbs heat from the atmosphere, and thus regains part or all of the ener y lost by the cooling of the gas. Again, a arge reserve store of gas is thus supplied to be drawn upon at each operation of the railway-traflic-controlling apparatus, so that the pressure for operating said apparatus remains more nearly uniform and the pressure-reducing means does not have to act form a part thereof, I have illustrated one form of apparatus by means of which my process may be carried into effect.

In the drawings, Figure 1 illustrates one form of the apparatus. Fig. 2 is a detail showing one means of operating the means for admitting gas to the apparatus. Fig. 3 is a detail section of the valve mechanism, and Fig. 4 is a section of the reducing-valve.

In the form of apparatus illustrated upon the drawings I have shown a signal as one species of railway-tmflic-controlling apparatus. In this form of the apparatus the signal includes a sign..l-blade 1. '1 his blade is normally biased toward one condition of indication by .ne.-.ns of the weight 2, provided with the usual glass spect..cle 3.

The weight is used to move the signalblade to the danger position.

Any desired means may be used for moving the signal-blade to safety. In the apparatus illustrated upon the drawings I have shown a motor mechanism 4,which may be connected to the signal in any desired manner. One form of the connecting means, as illustrated in the drawings, comprises a connecting-rod 5, pivoted to the moving part of the motor mechanism at one end and to the semaphore at the other.

In the apparatus illustrated in the drawings the motor mechanism comprises a piston 6 and piston-chamber 7. I have shown the piston-chamber as movable and the piston 6 as fixed but it will be understood that the piston may be movable and the pistonchamber fixed.

The form of the motor mechanism used to actuate the signal may be widely varied. I prefer to make use of a motor that is actuated M in one direction by the gas.

The high-pressure gas used to actuate the motor mechanism may be of any suitable kind. I prefer to make use of a gas that can be liquefied at ordinary temperatures, and in the best embodiment of my invention I make use of liquefied carbonic-acid gas. The pressure of liquefaction of this gas is high compared with the pressures used in the compressed-air system of operating signals, the pressure of liquefaction of said gas reaching from siX hundred to one thousand pounds per square inch, according to the temperature.

I prefer to store a supply of liquefied carbonic-acid gas locally in a suitable flask located near the signal. I have indicated such a flask at 8 upon the drawings. It will be understood that I may use a single flask for eaqih signal or one flask for a plurality of signa s.

Owing to the high pressure at which the gas is confined inthe flask 8 it is necessary to reduce the pressure thereof before the gas enters the motor for actuating the signal. The form of the means for reducing the pressure of the gas may be widely varied. In the apparatus illustrated upon the drawings I make use of an ordinary form of reducing-valve, such as described in the patent to Nageldinger, No. 519,089, May 1, 1894. A section of this valve is shown in Fig. 4.

The gas at a high pressure, the amount of which'is indicated by one of the hands of the pressure-gage 9, enters the reducing-valve nirough the pipe 10. 11 indicates the cap which closes the valve, the cap being mounted on a diaphragm 12 by means of a standard 13. A spring 14, adjusted by a screw 15, oppos s i.s force to that of the diaphragm 12 and to the pressure of the gas upon the diapliragm. The gas at the low pressure passes out of the low-pressure chamber of the valve at 16. The pipe 17 leads to the lowpressure side of the gage 9, one hand of which indicates the low pressure to which the gas. has been reduced. The operation of the valve will be clear from the description. When the pressure on the low-pressure side of the valve drops, the valve opens slightly until sufficient gas enters through 10 into the lowpressure chamber so that the effective pressure exerted by the gas on the diaphragm is sufficient to balance the pressure exerted by the spring 14, and thus close the cap 11.

When the pressure of the gas is reduced, the gas becomes chilled partly by reason of the cooling produced by the converting of the liquid in the flask 8 into gas and partly by the expansion of the gas as it passes through the reducing-valve. The amount of this chilling and the rapidity thereof depend in part upon the demand for gas that is made by the motor 4 and upon the amount and rate of supply of heat energy to the gas.

IIS

I have found, especially in the winter-time, when the parts of the apparatus are cool, that the chilling of the gas attendent upon its reduction in pressure is apt to produce and may sometimes produce solid particles of the substance of which the gas is composed. WVhen carbonic-acid gas is utilized, particles of carbonic-acid snow are thus formed and may reach the part of the apparatus beyond the reducingvalve. When the solid turns into gas by reason of its rise in temperature, due to heat supplied from the atmosphere, the volume of gas produced will greatly increase the pressure of the gas. This increase in pressure above a predetermined point may be suflicient to exert an injurious pressure upon the admission-valve, as will appear more fully hereinafter.

It is the object of my invention to prevent a rise in pressure over a predetermined.

amount both by preventing the formation of snow and by avoiding an injurious rise in pressure after any snow has formed.

My process may be widely varied to prevent the gas at the reduced pressure from rising in pressure above a predetermined point and to prevent an objectionable increase in the pressure of the gas, with its consequent injurious effectupon the admission-valve and its controlling mechanism. In the apparatus illustrated upon the drawings I store the gas in a reservoir 19 of suitable capacity, which reservoir is connected between the device for reducing the pressure of the gas and the admission -valve. Should any frozen solid be entrained by the gas and find a resting place in the space in front of the admission-valve, the reservoir will be of sufficient capacity to reduce the pressure of any gas resulting from the gasifi cation of the frozen solid. Storing the gas, moreover, will tend to prevent the formation of any solid and will also supply a larger reserve supply of gas at a reduced pressure to actuate the motor mechanism. The mass of gas that has passed the reducing-valve is not diminished, so that no gas is wasted. Moreover, storing the gas will permit the gas to receive heat from the surrounding atmosphere, and thus increase its stock of energy. Any suitable amount of gas may be stored. It is customary to store a number of times the amount of gas used by the cylinder of the motor at each full stroke.

It will be noted that the force necessary to actuate the admission-valve may be very small, with a consequent saving of the amount of battery necessary to actuate the electromagnet that I prefer to use to control said valve, and a consequent increased certainty and regularity of the action of the valve-com trolling mechanism is thereby effected for by means of my invention the pressure of the gas is prevented from rising more than a predetermined amount, and the pressure is never permitted to rise to such an extent and to press upon the admission-valve with such force as to interfere with its operation by the electromagnet and the electrical circuit which controls it.

Any 'desired means may be used to hold the railway-traffic-controlling apparatus in one position, and in particular any desired means may be used to hold the signal at safety. I have indicated the use of gaspressure for this purpose; but a detent may be used-as shown, for example, in the pat.- ent to C. J. Coleman, No. 743,975, November 10, 1903.

Any desired means may be used for ad mittin' gas at a reduced pressure to the motor. n the apparatus illustrated upon the drawings I make use of an admission-valve 20. This valve may be operated in any desired manner. In the said apparatus I make use of an electromagnet 21 for actuating said valve in one direction. Any desired connections may be used between the electromagnet and the valve. As illustrated upon the drawings, I make use of a pivoted armature 22, a connecting-rod 23, and a lever 24, pivoted at 25 to the bracket 26. The valve 20 is preferably connected to the lever 24 by means of a valve-rod 27. Any desired means may be used to return the valve. In the form of the valve mechanism illustrated in the drawings I make use of the weight of the parts assisted by gas-pressure to return the valve. It will be understood that any desired form of exhaust mechanism for permitting the gas to exhaust from the motor may be used. In the form of valve mechanism illustrated upon the drawings I connect the exhaust-valve 28 so as to move in unison with the admission-valve 20. This is preferably done by mounting both valve 28 and valve 20 on the same stem. The seat for the valve 20 is indicated at 20*, and the seat for the valve 28 is indicated at 28 The seat 20 is mounted in a screw-plug 29, which screws into the casing 30. Said casing is provided with a screw-threaded inlet-pipe 31, leading toward the tank 8, and a screwthreaded outlet-pipe 32, leading toward the motor. There is also provided a screw threaded cap 33, screwing into the casing 30, said cap being removable, so as to enable one to get at the admission-valve and the mechanism connected therewith. The gas entering at 2O passes into the chamber formed in the screw-plug 33, then down through the port of the admission-valve when this valve is open to the outlet-pipe 32, and thence to the motor. The exhaust-valve 28 is closed when the admission-valve 20 is open. When the admission-valve 20 is closed and the exhaust-valve 28 is opened, gas escapes from the motor and passes out to the atmosphere, the signal moving to danger. Any appro- IIO priate means may be used to control the ad mission-valve. In the apparatus illustrated upon the drawings I make use of electrical circuits, and I prefer to control said circuits by a train on the track. The form of this controlling mechanism may be widely varied, and it may be varied so as to control the operation of a normal safety or a normal danger system of railway-signals and of a system using a detent to hold the signal at one position or using gas for this purpose. In the apparatus illustrated upon the drawings the electrical circuit 34, which includes the battery 35, is normally closed by means of the circuit-closer 36. This circuit-closer is controlled in any desired manner. In the apparatus illustrated upon the drawings I make use of an electromagnet 37, which is placed in circuit with the rails 38 and a track-battery 39.

The operation of the apparatus will be readily understood. When there is no train upon the track, the circuit-closer 36 will be closed, the magnet 21 energized, the admission-valve 20 opened, and the exhaustvalve 28 closed. Gas is admitted to the motor, and the signal stands at safety. When the train enters the track-section 38, the wheels of the train short-circuit the magnet 37, which opens the circuit-closer 36, the admission-valve 20 is forced to its seat, and the exhaust-valve 28 is opened. The weight 2 moves the signal to danger, the gas from the motor exhausting through the exhaust valve.

The sizes of the parts of the apparatus used in carrying out my process may be widely varied. I have found that good results are obtained with a local storage-tank which contains about fifty pounds of liquefied gas at a pressure from six hundred to one thousand pounds per square inch at ordinary atmospheric temperatures, the pressurereducing means reducing the pressure to forty pounds per square inch. With such an apparatus the reservoir 19 contains about one hundred and forty cubic inches and the capacity of the cylinder 7 at the end of a fullstroke movement is about twenty-two cubic inches. On a busy railroad the railwaytrafiic-controlling device may be operated as often as one hundred times per day.

It will be understood that my invention is not limited to any particular theory of oper ation, nor to any particular time or manner of its use, and that wide departures may be made from the form or embodiment of the invention disclosed in this specification with out departing from the principle thereof.

What I claim as new, and desire to secure by Letters Patent, is

1. The process of utilizing liquefied gas for controlling railway traffic, which consists in permitting a small quantity of the liquid to e converted into gas, permitting the gas to expand intermittently into a reservoir of large capacity, and intermittently allowing a small quantity of said gas to actuate a gaspressure applying device to control said trafiic.

2. The process of utilizing liquefied gas for controlling railway traflic, which consists in permitting a small quantity of liquid to be converted into gas by reducing-the pressure on the liquid, permitting the gas to expand intermittently into a reservoir of large capacity, supplying heat to the gas during and after such expansion and intermittently allowing a small quantity of said gas to actuate a gas-pressure-applying device to control said traffic.

3. The process of utilizing liquefied gas for controlling railway trafiic, which consists in permitting a small quantity of the liquid to be converted into gas by reducing the pressure on the liquid, permitting the gas during short periods of time and intermittently to expand into a reservoir of large capacity, supplying heat to the gas during and after such expansion and intermittently allowing a small quantity of said gas to actuate a gas-pressureapplying device to control said traffic.

4. The process of utilizing liquefied gas for controlling railway trafiic, which consists in permitting a small quantity of liquid to be converted into gas by reducing the pressure on the liquid, permitting the gas to expand during short periods of time and intermittently into a reservoir of large capacity, allowing the gas to remain in said reservoir for longer periods of time so as to permit a supply of heat to the gas and intermittently allowing a small quantity of said gas to actuate a gas-pressure-applying device to control the traffic.

5. The process of utilizing carbonic-acid gas for controlling a railway signal, which consists in automatically and intermittently reducing the pressure of the gas, intermittently permitting the gas to expand into a reservoir of large capacity and intermittently causing the gas to operate a railway-signal.

6. The process of utilizing liquefied carbonic-acid gas for controlling a railway-signal, which consists in permitting a small quantity of the liquid to be converted into gas by reducing the pressure on the liquid, permitting-the gas to expand intermittently into a reservoir of large capacity, supplying heat to the gas and intermittently allowing a small quantity of the gas to actuate a gaspressure-applying device to control said signal.

7 The process of utilizing carbonic-acid gas for controlling a railway-signal, which consists in permitting the gas to expand during short periods of time and intermittently into a reservoir of large capacity, allowing the gas to remain in said reservoir for longer periods of time and intermittently allowing a small quantity of the gas to actuate a gasprrizssure-applying device to control the signa 8. The process of utilizing carbonic-acid gas for controlling a railway-signal, which consists in automatically and intermittently reducing the pressure of the gas, supplying heat to the gas while its pressure is being reduced, allowing the gas to expandinto a chamber of large capacity, supplying heat to the gas while in said chamber and intermittently permitting a part of the gas in said chamber to expand into a gas-pressure-applying device for actuating a railway-signal in one direction.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CLARENCE W. COLEMAN.

Witnesses:

A. K. GALE, WM. N. TowNLEY. 

